General Motors has set a different kind of bottom line for car companies, reducing and reusing waste material to zero at more than half of its manufacturing plants around the world.

PepsiCo’s Frito-Lay is taking similar action in food manufacturing, building what it calls a “netzero” plant in Arizona designed to operate on recycled water, solar-panel energy, biomass fuel and cutting edge waste reduction.

“This is an investment in our future. This is an investment in environmental sustainability,” Al Halvorsen, a Frito-Lay executive, said during a panel discussion at the Society of Environmental Journalists annual conference recently. “For businesses to succeed, societies must succeed as well,” he added in a rare discussion with a roomful of journalists about corporate moves to reduce their impact on the natural environment.

GM showcased its “green business” stance by displaying its newest Chevy Volt hybrid-electric car at the Society of Environmental Journalists conference in Lubbock, Texas in October. While many conference participants were drawn to test-drive the Volt, my attention was hooked by large posters highlighting GM’s “landfill free” actions at scores of facilities. The posters flanked a literature table headed by the company’s environment and energy communications manager, Sharon K. Basel.

“If you put a bag of trash on the curb each week,” Basel told the Detroit News in April, “you’re putting more trash on the curb than our 99 (landfill-free) facilities combined.”

This is an astounding development, given the massive flow of industrial debris dumped by auto manufacturers over decades that created toxic waste sites across the US. How did GM do this? Creative step by step, the Detroit News reported. “For example, engineers converted Chevrolet Volt battery-pack covers that were scrapped during the development process into wood-duck nesting boxes at the Wildlife Habitat Council-certified grounds of GM’s Customer Care & Aftersales Center in Grand Blanc.

“‘A lot of the stuff we’ve incorporated has come from employee ideas,’ Basel said. For GM, recycling means dollars, too. The company has recorded about $2.5 billion in revenue since 2007 by selling recycled materials.”

This is a business-oriented environmental story I don’t recall seeing reported previously. It gets more interesting the further I dug into it when I got home from the conference.

“In a sustainability report published last January … GM said its number of landfill-free facilities rose from 0 in 2000 and 1 in 2005 to 76 in 2010, and in that year its facilities recycled 92 percent of the waste they generated. In the report, GM committed to achieve 25 more landfill-free sites and reduce total waste by an additional 10 percent by 2020,” Environmental Leader website reported in June.

Among GM’s innovative actions, the environmental and energy management news site noted, are these: “The company has been re-purposing a wide variety of material. In conjunction with its suppliers, GM recycles scrap cardboard from various plants into a sound absorber on the Buick Lacrosse and Verano interior roof. Air deflectors on the Chevrolet Silverado and GMC Sierra pickup trucks are made with used tires from the automaker’s proving ground.”

In a business culture that traditionally emphasizes trade secrets, GM executives decided to tell other companies how they managed these improvements. “GM is sharing the lessons it’s learned with other corporations, such as PepsiCo’s Frito-Lay,” The Detroit News reported. “‘That is a big focus for us, to help mentor and train and share our best practices with other companies,’ Basel said.”

GM created a blueprint for landfill-free waste reduction and posted it on its website. “In the blueprint, GM gives nine steps on how to make plants and facilities landfill free such as tracking waste data, defining zero waste, prioritizing waste-reduction activities, engaging employees and building a sustainability culture, strengthening supplier partnerships, and resolving regulatory challenges,” Waste & Recycling News reported last month.

Why are big corporations like GM and Frito-Lay acting like environmental activists?

“Sustainability really isn’t a choice any more,” Sharlene Leurig, senior manager of water and insurance programs at Ceres, said during the SEJ panel discussion on “Green Businesses.” Ceres is a coalition focused on sustainable business practices. What got business executives’ attention, she said, is “the scale of disruptions” in doing business because of water shortages in drought areas and “extreme weather events” erupting around the world.

“The climate is changing,” Leurig said. “Companies are noticing.”

Halvorsen, the Frito-Lay executive, said multinational companies take supply disruptions from weather-related disasters very seriously—such as floods in Thailand that closed manufacturing supply plants. Many businesses now work with conservation groups on issues such as deforestation that contribute to more severe floods, for instance.

“We are active with about 400 corporations to try to improve sustainability in the world,” he said.

Halvorsen said his company and others are looking to change what goes on in agricultural and other practices in their supply chain that impact the environment. “There’s some dramatic things we can do,” he said.